Device for treating human and/or animal tissue

ABSTRACT

A device for working human and/or animal tissue is provided. The device includes a drill head is connected with a flexible shaft which in turn is connected to a drill apparatus through a shank. The device also includes a washing unit through which drilled material in the area of the drill head is transported away. The washing unit is connected to a washing channel formed between the bore and the outer diameter of the flexible shaft. The drill head has slots communicating with an inner cavity of the drill head. The cavity communicates with an inner channel in the flexible shaft through which the washing medium is passed into a washing head. In the washing head, the washing medium flows through the slots in the flexible shaft into an annular groove. The annular groove is connected with a channel to which a suction device is connected via a hose.

FIELD OF THE INVENTION

The present invention refers to a device for working on human and/oranimal tissue, in particular an arthroscope, an endoscope or a coredrill, in particular a intramedullary reamer for long bones such asfemurs.

DISCUSSION OF THE BACKGROUND ART

Arthroscopy is used to enter cavities in human or animal joints so as towork on the surface of a bone, for example. This work may be thesmoothing of the surface. Further, arthroscopy is also useful inremoving tissue, such as in the removal of bone parts from joints bymilling, scraping and the like. In endoscopy, human tissue is treated insimilar fashion; however, endoscopy is not employed in joint cavitiesbut in any other part of the human or animal body.

With fractures of long tubular bones such as femurs, both bone parts arefirst aligned and then bored in the longitudinal direction.Subsequently, a nail is inserted into the bore to fix both bone parts.

The bore is provided by first inserting a guide pin into the bone marrowof both bone parts. The guide pin is a wire with a diameter of 2 to 3mm. The guide pin serves to guide a drill head. The drill head isconnected to a flexible shaft driven by a drill drive, such as apneumatic drill.

When forming the bore, high pressure is generated at the drill head.This pressure pushes bone and fat tissue into venae. In this context,there is a chance of those particles being transported into the lung viathe blood vessel and causing pulmonary embolism. In particular, ifbesides the bone fracture also the lungs are injured, the two bone partscannot be fixed by the nailing describe above since the risk ofpulmonary embolism would be too high. Thus, the bone can only be fixedfrom outside. As a consequence, the fracture often heals poorly, anproper anatomic setting of the fracture is difficult, infections of thesoft-tissue environment occur frequently, and, possibly, the definitetreatment of the fracture has to be performed in a second surgicaloperation.

CH 687 228 A5 discloses a special drill head for intermedullary reamingdesigned to reduce the pressure at the drill head. The drill head hasopenings through which the drilled material, primarily the bone marrow,can be transported rearward. However, since a flexible shaft is locatedin the drill hole, there is only little space for accommodating thedrilled material. Thus, the amount of drilled material is larger thanthe space behind the drill so that the drilled material is furthercompressed. Thus, pressure builds up in the area of the drill head. Thismay result in drilled material being washed out into the lung via bloodvessels and causing pulmonary embolism.

The problems of increased pressure build-up are also disadvantageouswhen endoscopes and arthroscopes are used and may cause the abovementioned problem, respectively.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a device for working onhuman and/or animal tissue, in particular a core drill, especiallyuseful for intermedullary reaming in tubular bones, which avoidspressure build-up at the working head.

When the device of the present invention is a core drill, it comprises awashing unit by which the drilled material is transported away from thearea of the working head. In a core drill, the working head is a drillhead. By continuously washing, the material removed, i.e., the drilledmaterial, is washed out from the medullary space of the bone, forexample, so that no pressure can be generated within the bone andespecially at the drill head. Due to the pressure-less core drillaccording to the present invention, the risk of drilled material beingwashed into the lung and, thus, the risk of pulmonary embolism isavoided.

According to the invention, the core drill comprises a flexible shaftwith an inner channel. Further, the drill head connected to the flexibleshaft has openings in communication with the inner channel. According tothe invention, a washing unit is provided, having a contact surface thatallows the washing unit to be applied to an object in a substantiallysealed manner. If the core drill is used for intermedullary reaming, theobject is a tubular bone. Further, according to the invention, thediameter of the working head, as well as that of the drill head, islarger than the outer diameter of the flexible shaft so that a washingchannel is formed between the outer surface of the flexible shaft andthe drill hole produced in an object, such as a tubular bone.

When drilling tubular bones, a washing medium is introduced into thewashing channel from the washing unit. Thus, the washing medium flowsalong the outer surface of the flexible shaft towards the drill head.Since the washing unit has a contact surface that substantially sealsoff the bone surface, the washing medium can be introduced into thewashing channel in a simple manner. At the drill head, the washingmedium flows into the interior of the drill through the openings in thedrill head. In the process, the washing medium takes up the drilledmaterial and transports the same inward through the openings in thedrill head. Since the openings communicate with the inner channel of theflexible shaft, the washing medium is transported into the interior ofthe flexible shaft. In the inner channel of the flexible shaft, thewashing medium and the drilled material are carried out from the bonetowards the washing unit.

The washing medium may also be transported in reversed directions, sothat the washing medium flows through the inner channel of the flexibleshaft to the drill head, leaves from the openings thereof and isdischarged from the bone through the washing channel. However,discharging the washing medium through the inner channel of the flexibleshaft is advantageous in that the drilled material is not guided alongthe inner wall of the bore. This could cause the drill hole to becomeclogged and might thus lead to injuries at the inner wall of the bore.

Providing a washing unit is further advantageous in that no heat isgenerated at the drill head that could cause tissue changes.

Preferably, the washing unit comprises a suction device to generate avacuum at the drill head. Generating the vacuum guarantees that alldrilled material is discharged immediately. Thereby, the occurrence ofpressure is avoided at the drill head, which could cause drilledmaterial to enter the blood vessels of a patient. Preferably, thesuction device is connected with the inner channel of the flexible shaftso that the washing medium is sucked out through the inner channeltogether with the drilled material. This is advantageous in that thesealing between the contact surface of the washing unit and the objectneed not be of a particularly well sealing design, since no highpressures occur at the contact surface in this direction of suction.

Preferably, the flexible shaft has a plurality of articulately connectedshaft segments. By providing a plurality of shaft segments, a uniformtorque can be transmitted. Compared to known flexible shafts of spirallywound wire, the flexible shaft of shaft segments has the advantage thatno catching and a subsequent sudden free rotation of the drill head bythe flexible shaft relaxing can occur. With flexible shafts of spirallywound wire, a corresponding torque can be built up by twisting the wire.When the drill head is suddenly released, the flexible shaft of twistedwire relaxes. Thereby, the torques transmitted become non-uniform.

Preferably, a hose is provided in the shaft having a plurality of shaftsegments. The hose seals the inner channel of the flexible shaft offagainst the washing channel, since drilled material could otherwise getbetween the individual shaft segments and into the washing channel.Further, the drilled material could impair the flexibility of the shaftif drilled material accumulates between the individual shaft segments.With a reversed transport direction of the washing medium, i.e., ifdrilled material is discharged through the washing channel, the flexibleshaft should be enclosed by a hose to avoid drilled materialaccumulations between the shaft segments.

The washing unit, which is applied on the outside of an object or abone, preferably comprises a washing head. The flexible shaft isrotatably held in the washing head. The washing medium transportedoutward through the inner channel of the flexible shaft, enters thewashing head from the inner channel and is discharged therethrough. Tothis end, the flexible shaft has openings in the area of the washinghead, while the washing head has an annular groove so that despite therotation of the flexible shaft, the washing medium and the drilledmaterial can be discharged from the inner channel into the annulargroove and from there outward.

Preferably, the washing head is displaceably supported in a guidingelement of the washing unit. Thus, the contact surface of the washingunit can be held firmly on the object or the bone and simultaneouslyserves as a guide for the flexible shaft and the drill head. Theflexible shaft is thus guided in the guiding element together with thedrill head and the washing head so as to make the bore in the object orthe bone.

The flexible shaft preferably comprises a plurality of shaft segments.Each shaft segment comprises at least one projection and a recessengaging a recess or a projection of an adjacent shaft segment so thatprojections and recesses interlock. The dimensions of the projectionsand recesses are adjusted to each other such that a gap is formed thatextends around the shaft circumference. The interlocking projections andrecesses of adjacent shaft segments are further designed such that theyengage behind each other in the longitudinal direction. Thereby, theshaft segments are permanently connected in the longitudinal directionof the shaft. Due to the circumferential gap, a mutual play between theindividual shaft segments is obtained.

Depending on the magnitude of the play and the length of the individualshaft segments, the shaft is more or less flexible. By rotating a shaftsegment connected to the drive, the gap between the shaft segments isclosed partly so that the opposing gap surfaces are partly in contact.Power is transmitted via these contact areas from one shaft segment tothe next. In this manner, the flexible shaft transmits a torque. Totransmit higher torques, the shape of the projections and recesses maybe designed such that contact areas as large as possible are obtainedwhen rotating the shaft.

The individual shaft segments are preferably inherently rigid. They arepreferably made of hard plastic material or metal and, especially, oftitanium. Since the projection of one shaft segment engages into therecess of an adjacent shaft segment, the projection engages behind therecess, as provided by the invention. Thus, the projection comprises aneck-shaped and a head-shaped part. Similarly, the recess comprises aneck-shaped and a head-shaped part. The shaft segments are therebypermanently connected in the longitudinal direction. The design of theprojections and recesses of the present flexible shaft also serves totransmit traction and pressure forces. The areas of the gap surfaces inwhich the shaft segments contact each other when transmitting tractionor pressure forces, may preferably be formed such that a transmissionsurface is formed to reduce the surface pressure.

Preferably, each shaft segment has at least two projections and tworecesses on the shaft circumference. The surface for force transmissionbetween two shaft segments is thus increased. Preferably, theprojections are of the same size and are arranged regularly along thecircumference of the shaft. Thus, it is guaranteed that the flexibleshaft has approximately the same flexibility in every direction ofbending. Preferably, the ratio between the gap width and the shaftdiameter is between 1:100 and 1:10 for round shaft segments. This meansthe gap width is between 0.1 and 1 mm for a shaft diameter of 10 mm. Theselection of the gap width can influence the maximum possible bending ofthe flexible shaft. In order to increase the reliability of thetransmission of torques, as well as of forces, it is advantageous toprovide gap widths as small as possible, i.e., a gap width of only 0.5to 0.1 mm for a shaft diameter of 10 mm. To increase flexibility, notthe gap width should be increased, but the number of shaft segments byshortening the length of the individual shaft segments.

In medical applications, the present core drill is suitable not only asan intermedullary reamer, but also for loosening and washing outangiosclerosis as well as for removing nephroliths, uretheroliths andgallstones. To this avail, a gripping or catching device mayadditionally be provided at the drill head. According to the invention,the broken stones are carried away by washing.

The above described core drill is not only suitable for medicalpurposes, but for core drilling in general, where pressure build-up atthe drill head is to be avoided. This is the case, for example, when thematerial surrounding the drill hole could be damaged by the pressuregenerated upon drilling. The present drill is thus particularly suitablefor drilling soft plastic and natural materials. Since no pressure isbuilt up at the drill head in the present core drill, the drill isespecially well suited for brittle materials since these could bedamaged by the pressure. For example, hairline cracks could occur in thematerial.

The present core drill can be implemented both on a large scale and inmicro and nano technology.

After completion of the bore, material can be introduced into thedrilled object through the inner channel of the flexible shaft. Thus,the drilled hole can be filled with filling material immediately uponwithdrawing the drill, e.g. to stiffen the object.

In a preferred embodiment of the present invention, the flexible shaftitself can serve as a nail for connecting two bone pieces. To this end,the flexible shaft is connected or adapted to be connected with atensioning device for stiffening the shaft. The tensioning device closesthe gaps between the individual shaft segments. Thus, the tensioningdevice pulls the individual shaft segments together. Since the gap isdesigned such that tangential forces can be transmitted between theshaft segments, pulling the shaft segments together forms a non-flexibletube. The same may be used directly as a nail in a bone. Pullingtogether the individual shaft segments may be done, for example, bymeans of a suitable cable control or by compressing the flexible shaft.

Preferably, the flexible shaft further comprises an anchoring device foranchoring the shaft in the bone. Such an anchoring device is preferablydesigned such that, when the flexible shaft is tensioned, anchoringwedges or the like flip outward and cause the flexible shafts nowstiffened to form a nail, to be anchored in the bone. Of course, theanchoring can also be effected before or after stiffening the shaft.Further, it is also possible to separately introduce anchoring elementsinto the inner channel of the flexible shaft and to insert them throughcorresponding openings in the shaft so that an anchoring of the shaft inthe bone is achieved thereby.

The blades of the drill head are preferably formed such that the drillhead, as soon as it meets a harder sheath after drilling soft corematerial, is deflected back into the core material. Thus, it is avoidedthat the drill emerges laterally from the object to be drilled, such asthe bone.

The present invention for working on human and/or animal tissue,exemplified above by the core drill, is as well suitable for use as anarthroscope or an endoscope. The present arthroscope or endoscope alsocomprises a flexible shaft with an inner channel. The flexible shaft isconnected with a working head with which tissue can be removed bysmoothing, milling, scraping or the like, for example. The working headhas openings which communicate with the inner channel. Further, thepresent arthroscope or endoscope has a washing unit. Corresponding tothe above described core drill, the diameter of the working head, i.e.the maximum outer dimensions of the working head, which does not have tobe a rotating tool, has to be larger than the outer diameter of theflexible shaft. Thus, a washing channel is formed by the outer surfaceof the flexible shaft and a hole in the object, i.e. the human tissue,for passing a washing medium therethrough.

In the present arthroscope, an additional working channel could beprovided. For example, optics could be introduced therethrough in orderto watch the working process. Further, washing fluid can be suppliedthrough the working channel which can then be sucked off through theworking head and the washing channel between the flexible shaft and theinner wall of the drill hole.

An arthroscope or endoscope according to the invention may be designedin a preferred manner corresponding to the above described core drill.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a detailed description of the invention with referenceto the accompanying drawings.

In the figures:

FIG. 1 is a schematic side elevational view of the core drill,

FIG. 2 is a schematic sectional view of the portion II in FIG. 1, and

FIG. 3 is a schematic sectional view of the portion III in FIG. 1.

According to the invention, the core drill can be used in particular forcore drilling in a tubular bone 10, such as a femur . For this purpose,the core drill comprises a drill head 12 connected to a flexible shaft14. A shank 16 connects the flexible shaft 14 to the chuck of a drill,such as a pneumatic drill, for example. The core drill further comprisesa washing unit 18 for transporting away the drilled material occurringin the area of the drill head 12, using a washing medium. In the medicalfield, the washing medium preferably is a saline solution. In othertechnical fields gases or other liquid medium can be used as the washingmedium.

The washing unit 18 comprises an connection 20 connected by a hose to areservoir containing washing medium. The washing medium is passedthrough a channel 24 provided in a guiding element 22 of the washinghead 18. From the channel 24, the washing medium is supplied to acylindric cavity 26 within the guiding element 22. From there, thewashing medium flows into a washing channel 30 in the direction of thearrows 28. The washing channel 30 is provided between an outer diameterd of the flexible shaft 14 and the bore diameter D (FIG. 2). The borediameter D corresponds to the drilling diameter D of the drill head 12.The washing medium reaches the drill head 12 through the washing channel10 and is guided along blades 32 of the drill head 12. At the blades 32of the drill head 12, the washing medium receives drilled material. Whendrilling tubular bones, this is primarily bone marrow. The bone marrowis carried away by the washing medium. To this end, the drill head hasopenings in the form of longitudinal slots 34 through which the washingmedium can flow into the drill head 12.

The drill head 12 has a hollow interior so that the washing medium canflow through the slots 34 into the hollow interior 36 of the drill head12. From the hollow interior 36 of the drill head 12, the washing mediumflows in the direction of the arrows 38 into an inner channel 40 formedin the flexible shaft. The flexible shaft 14 is hollow along its entirelength so that the inner channel 40 extends from the drill head 12 tothe washing unit 18. The washing medium and the drilled material flowthrough the inner channel 40 to a washing head 42 provided in thewashing unit 18.

The flexible shaft has a plurality of shaft segments 44. Each shaftsegment has a plurality of projections 46 engaging into recesses 48 ofthe adjacent shaft segment 44. The projections 46 and the recesses 48are designed such that the projections 46 and the recesses 48 engagebehind each other in the longitudinal direction of the flexible shaft14. Thus, the shaft segments 44 are permanently connected in thelongitudinal direction. In order to guarantee the flexibility of theshaft 14, a gap is formed between the individual shaft segments 44 thatextends along the entire circumference of the flexible shaft 14. Thewidth of the gap and the length of the individual shaft segments 44define the flexibility of the shaft 14. The projections 46, as well asthe recesses 48, are preferably of the same size and are regularlyarranged on the circumference of the flexible shaft 14. Thus, it isguaranteed that the flexibility of the shaft 14 is the same in anydirection of deflection. Further, the gap has a constant width in thecircumferential direction.

Since the washing medium could get into the washing channel 30 throughthe gaps between the shaft segments 44, whereby drilled material couldget into the gaps and impair the flexibility of the shaft, the flexibleshaft 14 is lined with a hose 50. The hose 50 extends from the drillhead 12 to the shank 16.

The flexible shaft 14, via which the torque is transmitted from thedrill to the drill head 12, is rotatably supported in the washing head42 by bearings 52. Further, to be able to perform a drilling, thewashing head 42 is supported for displacement within the guiding element22 in the direction of the arrow 55, i.e. in the direction of drilling.Preferably, the washing head 42 is cylindrical so that it isdisplaceable in the cylindric cavity 26 of the guiding element 22. Inorder to avoid the washing head 42 from rotating along when drilling,the inner wall of the cylindric cavity 26 and the outer surface of thewashing head 42 are provided with guiding elements. These may be groovesand corresponding projections. A seal is provided between the outersurface of the washing head 42 and the surface of the cylindric cavity26 so as to prevent washing medium from escaping outward from thecylindric cavity 26 passing the washing head 42.

The washing medium transported from the drill head through the innerchannel 40 in the flexible shaft towards the washing head 42 leaves thewashing head 42 through a channel 54 and enters a hose 56 connected to acollecting vessel. For this purpose, the washing head has an annulargroove 58. On the level of the annular groove 58, the flexible shaft 14comprises a plurality of longitudinal slots 60 through which the washingmedium flows from the inner channel 40 into the annular groove 58. Thehose 56 is preferably connected with a suction device so that a vacuumis created at the drill head 12. This guarantees that no pressures occurin the area of the drill head when drilling the bone 10 which couldcause drill medium to be transported, e.g. bone marrow being transportedin venae. Thus, the risk of pulmonary embolism caused by drilledmaterial being transported into the lungs is avoided.

The inner side, in particular at the end facing the drill head 12, theflexible shaft can have projections that cause the washing medium torotate. For example, these are blade-like projections. Further, a kindof Archimedean screw may be provided. The inner side of the hose 56 mayalso be provided with a helical groove or a helical projection. Suchelements cause the washing medium to rotate and the transport of thedrilled material is improved.

In the upper portion of the shank 16, the inner channel 40 of theflexible shaft 14 is sealed by a seal 62 from the drill apparatus.

On the side facing the bone 10, the guiding element 22 of the washingunit has a contact surface 64 abutting the bone 10. By the contactsurface, the washing unit 18 is sealed from the bone 10 so that no oronly little washing medium can escape outward from the cylindric cavity26 along the contact surface 64 and into the tissue surrounding the bone10. In addition, washing medium is prevented from escaping along thecontact surface 64 by providing a suction device at the hose 56 so thatno increased pressures occur in the area of the cavity 26.

In order to avoid the drill head 12 of the core drill to penetrate theouter wall of the bone from the intermedullary space of the bone 10outward, the blades of the drill head 12 are designed such that uponhitting the bone wall, i.e. harder material, from inside, the drill head12 is deflected back into the intermedullary space. Thus, perforatingthe bone, i.e. a lateral escape of the drill head from the bone, isavoided.

This may also be achieved by providing a guide wire 66. The guide wire66 extends through the shank 16, the hollow flexible shaft 14 and thedrill head 12.

To effect a core drilling using a guide wire 66, the guide wire of adiameter between about 2 to 3 mm is first inserted through the bone.During the subsequent drilling of the bone 10, the drill head 12 isautomatically guided by the guide wire 66 so that the drill head 12cannot escape laterally from the bone 10. To make the bore in the bone10, the guide wire 66 is thus introduced first. Then, the contactsurface 64 of the washing unit 18 is set onto the bone. Thereafter, thewashing head 42 is introduced into the cylindric cavity 26 of theguiding element 22 so that the drill head 12 contacts the bone 10 on thelevel of the contact surface 64. Then, the drill head 12 is rotated bythe drill apparatus and moved in the direction of the arrow 55 togetherwith the flexible shaft 14 and the washing head 42.

The washing unit 18 may be designed such that it does not serve as aguide for the washing head 42. In this embodiment, the cavity 26 is notsealed from the washing head 42 but from the outer surface of theflexible shaft 14. This is advantageous in that the guiding element 22does not have to have the entire length of the bore.

1. A device for working human and/or animal tissue comprising: aflexible shaft with an inner channel, a working head connected with theflexible shaft and having openings communicating with the inner channel,and a washing unit with a contact surface for a substantially sealedapplication on object, the diameter of the working head being greaterthan the outer diameter of the flexible shaft so that a washing channelis formed by the outer surface of the flexible shaft and a bore made inthe object, the washing channel serving to pass a washing mediumtherethrough, wherein the flexible shaft has a plurality of articulatelyconnected shaft segments and a hose is provided in the flexible shaft.2. A device for working human and/or animal tissue comprising: aflexible shaft with an inner channel, a working head connected with theflexible shaft and having openings communicating with the inner channel,and a washing unit with a contact surface for a substantially sealedapplication on an object, the diameter of the working head being greaterthan the outer diameter of the flexible shaft so that a washing channelis formed by the outer surface of the flexible shaft and a bore made inthe object, the washing channel serving to pass a washing mediumtherethrough, wherein the washing unit comprises a washing head in whichthe flexible shaft is rotatably supported.
 3. The device of claim 2,wherein the washing head is supported for displacement in a guidingelement of the washing unit.
 4. A device for working human and/or animaltissue comprising: a flexible shaft with an inner channel, a workinghead connected with the flexible shaft and having openings communicatingwith the inner channel, and a washing unit with a contact surface for asubstantially sealed application on an object, the diameter of theworking head being greater than the outer diameter of the flexible shaftso that a washing channel is formed by the outer surface of the flexibleshaft and a bore made in the object, the washing channel serving to passa washing medium therethrough, wherein the flexible shaft has aplurality of shaft segments with mutually engaging projections andrecesses which engage behind each other in the longitudinal direction,leaving a gap around the shaft circumference, so that the shaft segmentsare permanently connected in the longitudinal direction having mutualplay.
 5. The device of claim 3, wherein all projections are of the samesize and are distributed regularly over the circumference of the shaft.6. The device of claim 3, wherein the gap has a constant width in thecircumferential direction.
 7. The device of claim 3, wherein the ratioof gap width and shaft diameter is between 1:100 and 1:10.